Analytic Sample Preparation MethodsSpecimen HandlingChemistry Techniques, AnalyticalSpectrometry, Mass, Matrix-Assisted Laser Desorption-IonizationSensitivity and SpecificityReproducibility of ResultsPolymerase Chain ReactionUnited StatesFood, PreservedCookingBisacodylHistocytological Preparation TechniquesLongitudinal StudiesDrug CompoundingCohort StudiesMicrowavesParticle SizeTandem Mass SpectrometryReference StandardsMass SpectrometryCross-Sectional StudiesChemical FractionationChromatography, High Pressure Liquid